My partner and I work at the same company. There are no regs against dating coworkers. But we are worried about being gay and coming out. What is the "PC" way to do this so it doesn't cause any problems? Do we even need to come out to coworkers?

Since there are no barriers to dating coworkers, why would you think you two need to come out? It seems to be no different than any straight relationship. It's no one else's business unless you make it their business. Is it possible you are still uncomfortable with being gay? No need. You're fine however you are.